Novel insecticides, acaricides and nematocides



United States Patent 2,908,474 -3 NOVEL INSECTICIDES, ACARICIDES AND NEMATOCIDES Karoly Szabo, Yonkers, N. and John G. Brady and.

The present invention is concerned with certain novel compounds useful as insecticides, acaricides and nematocides, and with novel methods for their preparation.;

The compounds of the present invention have the toomula R s Y wherein R and R are selected from the group consisting of methyl and ethyl and Y is selected from the group consisting of hydrogen and alkyl groups having up to four carbon atoms.

The novel compounds can be made by the reaction of a compound having the formula a powder., For example, they may be made into the format a wcttable powder by the addition of a finely divided ground carrier or diluent such as Attaelay, a

finely divided clay, containing'a suitable wetting agent such as a'hlgher aliphatic alcohol, sulfate Wettingagent. Powders of this sort may readily be mixed with water and applied as dispersions to infested plants.

The following examples are given solely for the-purpose of illustration and are not. to be construed aslh'gnitations of the present invention. many variations of job will occur to those chilled in the art'without departing from the spirit or scope thereof.

EXAMPLE I 0-ethyl-S-P-tolyl-ethylphosphonadirhioate (Compound I) CsHa S s ucy...

phlethylbenzenethiol (12.4 g.), O-ethyl-ethylphosphonochloridothioate (17.3 g.) and acetone (70 ml.) are placed in a hash equipped with reflux condenser, thermometer, stirrer and dropping funnel. Tricthylamine' (10.1 g.) is added dropwise now while the reaction mixture is stirred. The addition isfollowed by an exothermic reaction with the precipitation of the formed tnie'thylamine hydrochloride. The addition is completed in 10 minutes. The temperature of the reaction mixture rises to 50 C. by that time. Then the mixture is brought to reflux for half an hour in order to complete the re action.

The amine hydrochloride is removed from the mixture 2,988,474 Patented June 13, 1961 by washing it with water. Traces of the uureacted thiophenol are extracted with a 3% NaOH solution.

The mixture,'washed to neutral with water, is dried on MgSO The solvent and by-products are removed at reduced pressure and elevated temperature (end point 0.5 mm. and C.). The residue is treated with charcoal and filtered with suction to yield 24 g. of a yellow oil which has a refractive index of 1.5897 at 25 C.

Yield 92%. It has been analyzed as follows:

Calcd..: =50.7%; H=6.5%; S=24.6.

C=50.80%; H=6.33%; S=23.66.

OaHi 8 CIHIO O-methylbenzenethiol (11.7 g.), O-ethyl-ethylphosphonochloridothioate (16.4 g.) and acetone (70 ml.) are brought together and Et N- (10 g.) is added in portions while the mixture is elficiently stirred. An exothermic reaction takes place with the prompt precipitation of the amine hydrochloride. When all the triethylamine is added the mixture is refluxed (58 C.) for 20' minutes then allowed to cool down.

Benzene (70 ml.) is added and the mixture is successively washed with water, 3% NaOH and water again. The benzene layer is separated and dried over anhydrous MgSO Q Then the solvent is stripped oil. to obtain a crude oily product in an. amount of 18 g. (73% yield) with an N of'1.'5918.

The pure compound boils at C. at a slightly yellowish oil of an N of 1.5892.

Analysis-Called: C=50.7; H=6.5; S=24.6; P=11.9. Found: C=50.78; H=6.63; S=24.15; P=12.21.

EXAMPLE III 0-ethyI-S-phenyl-ethylphosphonodithioale (Compound II) CIHI S CzHaO Found:

0.1 mm. It is The compound has been prepared by the method described under Example 11 using thiophenol instead of O-methylbenzenethiol. The crude product, a yellow oil with anN of 1.5888, has been obtained in a yield of 89%. The pure product distills at 130-32 at 0.1 mm. pressure. Its N is 1.5883.

Analysis.-Calcd.: C=48.8; H=6.1; P= 12.6. Found: C=49.1; H=5.92; P=11.16.

EXAMPLE 1v 5 O-ethyl- -(p-tert.-butylphenyl)-ethylph0sphonodithioate (Compound 11]) i EXAMPLE V The homologous O-methyl and methylphosphonodithioate compounds may be prepared by reactions analogous to the examples above, using the corresponding O-mcthyl and methylphosphonochlorothioates.

The compounds have been tested as insecticides and as acaricides according to the following methods:

Acaricidal evaluation test.-The two-spotted mite, Tetraanychus telaril'ls (Linn) is employed in tests for acaricides. Young pinto bean plants are infested with several hundred mites. Dispersions of test'compounds are prepared by dissolving half a gram of the toxic material in ten milliliters acetone. This solution is then diluted with water containing 0.015% Vatsol a sulfonatc-type wetting agent) and 0.005% Mcthocel (methyl cellulose) as emulsifiers, the amount of water being sufficient to give concentrations of active ingredient ranging from 0.25% to 0.005%. The test suspensions are then sprayed on the infested pinto bean plants. After seven and fourteen days, the plants are examined both for post-embryonic forms of the mite as well as eggs. The percentage of kill is determined by comparison with control plants which have not been sprayed and the LD-SO value calculated using well-known proeedures.

Insecticidal evaluation tests.-Four insect species are subjected to evaluation tests for insecticides:

(1) American cockroach, Periplaneta nmericmm (Linn.) (2) Large milkweed bug, Oncopeltus fosciatus (Dallas) (3) Confused flour beetle, Tribalium confusion (Duval) (4) House fly, Musca domestica (Linn) The procedurefor insects 1, 2, 3 and 4 is similar to r the miticidal testing procedure. Test insects are caged in cardboard mailing tubes 3 /8" in diameter and 2 /8 tall. The cages are supplied with cellophane bottoms and screened tops. Ten to twenty-five insects are used per cage. Food and water are supplied ineach cage. The confused flour beetles are confined in Petri dishes without food. The caged insects are sprayed with the active compound at various concentrations. After twenty-four and seventy-two hours, counts are made to determine living and dead insects.

Honse fly evaluation tests differ in this respect: the toxicant is dissolved in a volatile solvent. preferably acetone, the active compound is pipetted into a Petri I dish bottom, allowed to air dry and placed in a card- TABLE I Compound Compound Compound I II III House I lles.. t g 10 n: ltng American 1? each... .c. 0. 025% 0. 025% 0. -0. 1% Milkweed Bug 0.05% X 0. 1% Confused Flour Beetle. l0-10thm Iii-in 0.1%v 'lwo-Spotteri Mite. 0. 06?? 0. 06 l 0. Two-Spottod Mite- Eggs 0. 06% 1 0. 25

1 These figures yielded 100% kills. X represents low activity.

The nematocidal activity of the compounds of the present invention is illustrated by tests on O-ethyl-S- phenylethylphosphonodithioate, Compound ll above. Vvhen applied to the soil at concentrations as low as ten parts per million, the compound produced 100% mortal- 4 ity against root-knot nematodes. Even at a concentration of five parts per million, it was highly active, but gave somewhat less than mortality. Furthermore. even at relatively high concentrations the compound is non-toxic to plants.

What is claimed is:

1. As a new composition of matter a compound having the formula RIS Y wherein R and R are selected from the group consisting of methyland ethyl and Y is selected from the group consisting of hydrogen and alkyl groups having up to four carbon'atoms. 2. As a' new composition of matter: O-ethyl-S-p-tolylcthylphosphonodithioate.

.3. As a new composition of matter: O-ethyl-S-otolyl-ethylphosphonodithioate.

4. As a new composition of matter: O'ethyl-S-phenylcthylphosphonodithioate.

5. As a new composition of matter: O-ethyl-S-(p-tcrt.- butylphenyl)-ethylphosphonodithioate.

6. As a new composition of matter: phcnyl-ethylphosphonodithioate.

7. As a new composition of matter: O-ethvl-S-phenylmethylphosphonodithioate.

8.-A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient a compound having the formula O-methyl-S- wherein R and R are selected from the group consisting of methyl and ethyl and Y is selected from the group consisting of hydrogen and alkyl groups having up to four carbon atoms.

9.A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient O-ethyl-S-ptolyl-ethylphophonodithioate.

10. A method of killing pests comprising applying to a pest habitat a composition containing as the essential tive ingredient O-ethyl-S-o-tolyi-ethylphosphonodithioate.

11. A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient O-ethyl-S-phenyl-cthylphosphonodithioate.

12. A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient O ethyl-S-(p-tert.-butylphenyl)-ethylphosphonodithioate.

13. A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient O methyl-S-phenyl-ethylphosphonodithioate.

14. A method of killing pests comprising applying to a pest habitat a composition containing as the essential active ingredient O ethyl-S-phenyl-methylphosphonodithioate.

15. A method for preparing a compound having the formula wherein R and R are selected from the group consisting of methyl and ethyl and Y is selected from the group consisting of hydrogen and alkyl groups having up to four carbon atoms, comprising reacting a compound having the formula References Cited in the file of this patent UNITED STATES PATENTS Fairchild Oct. 27, 1959 FOREIGN PATENTS France June 15, 1959 Germany July 8. 1949 3 3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION I Patent No, 2,988,474 Dated June 13, 1961 Inventofls) Karoly Szabo, John G. Brady and Thomas Bruce Williamson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby. corrected as shown below:

Column 5, that portion of the formula reading:

S S IS: i should read g SIGNED KND SEALED MM 1 7 1970 (SEAL) .Attest:

Edward M. Fletcher, Ir; Attesting Officer WILLIAM E- SOHUYLER, JR.

Commissioner of Patentsand John G. Bmd and Thom Willi on, Santa Clara, Calif. NOVEL INSECTICIDES ACARICIDES AND NEMAT'OCIDES. Patent dated 19 e assignee, Staufer 07mm- June 13, lsclairner filed May 12, 1966, by th z'cal Oompany.

this disclaimer to claims 6 Oficz'al Gazette Octobe and 7 of said patent. 7' 4, 1966.] 

8. A METHOD OF KILLING PESTS COMPRISING APPLYING TO A PEST HABITAT A COMPOSITION CONTAINING AS THE ESSENTIAL ACTIVE INGREDIENT A COMPOUND HAVING THE FORMULA
 15. A METHOD FOR PREPARING A COMPOUND HAVING THE FORMULA 